1<?php
2
3/**
4 * Custom validation class, accepts DTD child definitions
5 *
6 * @warning Currently this class is an all or nothing proposition, that is,
7 *          it will only give a bool return value.
8 */
9class HTMLPurifier_ChildDef_Custom extends HTMLPurifier_ChildDef
10{
11    /**
12     * @type string
13     */
14    public $type = 'custom';
15
16    /**
17     * @type bool
18     */
19    public $allow_empty = false;
20
21    /**
22     * Allowed child pattern as defined by the DTD.
23     * @type string
24     */
25    public $dtd_regex;
26
27    /**
28     * PCRE regex derived from $dtd_regex.
29     * @type string
30     */
31    private $_pcre_regex;
32
33    /**
34     * @param $dtd_regex Allowed child pattern from the DTD
35     */
36    public function __construct($dtd_regex)
37    {
38        $this->dtd_regex = $dtd_regex;
39        $this->_compileRegex();
40    }
41
42    /**
43     * Compiles the PCRE regex from a DTD regex ($dtd_regex to $_pcre_regex)
44     */
45    protected function _compileRegex()
46    {
47        $raw = str_replace(' ', '', $this->dtd_regex);
48        if ($raw[0] != '(') {
49            $raw = "($raw)";
50        }
51        $el = '[#a-zA-Z0-9_.-]+';
52        $reg = $raw;
53
54        // COMPLICATED! AND MIGHT BE BUGGY! I HAVE NO CLUE WHAT I'M
55        // DOING! Seriously: if there's problems, please report them.
56
57        // collect all elements into the $elements array
58        preg_match_all("/$el/", $reg, $matches);
59        foreach ($matches[0] as $match) {
60            $this->elements[$match] = true;
61        }
62
63        // setup all elements as parentheticals with leading commas
64        $reg = preg_replace("/$el/", '(,\\0)', $reg);
65
66        // remove commas when they were not solicited
67        $reg = preg_replace("/([^,(|]\(+),/", '\\1', $reg);
68
69        // remove all non-paranthetical commas: they are handled by first regex
70        $reg = preg_replace("/,\(/", '(', $reg);
71
72        $this->_pcre_regex = $reg;
73    }
74
75    /**
76     * @param HTMLPurifier_Node[] $children
77     * @param HTMLPurifier_Config $config
78     * @param HTMLPurifier_Context $context
79     * @return bool
80     */
81    public function validateChildren($children, $config, $context)
82    {
83        $list_of_children = '';
84        $nesting = 0; // depth into the nest
85        foreach ($children as $node) {
86            if (!empty($node->is_whitespace)) {
87                continue;
88            }
89            $list_of_children .= $node->name . ',';
90        }
91        // add leading comma to deal with stray comma declarations
92        $list_of_children = ',' . rtrim($list_of_children, ',');
93        $okay =
94            preg_match(
95                '/^,?' . $this->_pcre_regex . '$/',
96                $list_of_children
97            );
98        return (bool)$okay;
99    }
100}
101
102// vim: et sw=4 sts=4
103